package com.jihu.shiro.demo.util;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.interfaces.DecodedJWT;

import java.io.UnsupportedEncodingException;
import java.util.Date;

//https://blog.csdn.net/qq_23250633/article/details/81063762
/**
 * jwt工具类
 */
public class JwtUtil {

    private static final  long EXPIRE_TIME = 5 * 60 * 1000;

    /**
     * 校验token是否正确
     * @param token 密钥
     * @param username 用户名
     * @param secret 用户的密码
     * @return 是否正确
     */
    public static boolean verify(String token , String username ,String secret){
        try {
            Algorithm algorithm =  Algorithm.HMAC256(secret);
            JWTVerifier verifier = JWT.require(algorithm)
                                    .withClaim("username",username)
                                    .build();
            //校验token
            DecodedJWT jwt = verifier.verify(token);
            return  true;
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 获取token中的信息无需secret解密也能获得
     * @param token token中包含的用户名
     * @return
     */
    public static String getUsername(String token){
        try {
            DecodedJWT jwt = JWT.decode(token);
            return  jwt.getClaim("username").asString();
        } catch (JWTDecodeException e){
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 生成签名，5min过期
     * @param username 用户名
     * @param secret  用户密码
     * @return
     */
    public static String sign(String username , String secret){
        try {
            Date date = new Date(System.currentTimeMillis() + EXPIRE_TIME);
            Algorithm algorithm = Algorithm.HMAC256(secret);

            //附带username信息
            return JWT.create()
                       .withClaim("username",username)
                       .withExpiresAt(date)
                       .sign(algorithm);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return null;
        }
    }

}
